What is a chimpanzee? Chimpanzees evolved in the Tertiary period, about five million years ago, when they split off from earlier primates in Africa. When did chimpanzees evolve? Chimpanzees are [...]
Chordates include this giraffe from Kenya What is a chordate? Any animal that has a spinal cord is a chordate. This group covers most of the creatures you see at [...]
A frog sitting half in the water: Evolution of frogs When did frogs evolve? Frogs developed out of lungfish about 375 million years ago, in the Devonian period. They used their [...]
Evolution of fish: a lungfish Why did fish leave the water? About 400 million years ago, during the Devonian period, the Earth was going through an especially warm period. Some [...]
History of fish: it looks like a severed tentacle but it's a lamprey. When did fish evolve? About 510 million years ago, in the Cambrian period, some of the worms [...]
A robin sits on a branch: birds biology When did birds evolve? The first birds evolved out of earlier small dinosaurs late in the Jurassic period, about 150 million years [...]
Fossil spider from the Cretaceous era Spiders evolved from annelid worms beginning about 540 million years ago. They were among the first land creatures with more than one cell. At about the same time, the [...]
Bee on a flower What are arthropods? Insects, spiders, crabs, and lobsters are all arthropods, so there are a lot of arthropods on Earth. Annelid worms All our biology articles [...]
Evolution of grasshoppers: Grasshopper sitting on a leaf Why do grasshoppers jump? When grasshoppers first evolved from earlier insects, about 300 million years ago, they lived in forests of huge [...]
Evolution of ants: A bunch of ants When did ants evolve? Ants evolved from earlier wasps about 150 million years ago, during the Cretaceous period. The evolution of ants was around [...]
